To preliminarily evaluate the fingertip′s microcirculation in rheumatoid arthritis (RA) patients without clinical manifestations of cardiovascular disease by high frequency ultrasonography and E-flow imaging.

From June 2012 to March 2013, 45 consecutive RA inpatients of affiliated hospital of North Sichuan Medical College without clinical manifestations of cardiovascular disease were enrolled. At the same time, 45 age-and sex-matched healthy volunteers were selected as the health control group. To observe the course and distribution characteristics of the fingertip vessels, peak systolic velocity (PSV), end diastolic velocity (EDV), mean velocity (MV), vascular resistance index (RI) and pulsatility index (PI) of digital palmar propria artery and nail bed arteries were measured. In addition, the ratio of pixels in vessels and nail bed was calculated. The arterial blood flow parameters of middle fingertip and the ratio of pixels in vessels-nail bed in RA group and healthy control group were compared using independent sample t test.

Compared to control group, PSV, EDV and MV of the digital palmar propria artery of middle finger was lower and RI of the nail bed arteries was higher in RA group (P>0.05), but there were no statistical differences between RA and control group. RI and PI of digital palmar propria artery and PI of nail bed arteries in RA group were higher than those of the control group (0.65±0.08 vs 0.62±0.06, 1.16±0.33 vs 1.02±0.18 and 1.17±0.32 vs 1.01±0.21), and the differences were statistically significant (t=-2.02, P=0.047; t=-2.09, P=0.041; t=-2.06, P=0.043). In addition, it was statistically significant between RA and control group (t=3.68, P<0.01) and the ratio of pixels in vessels and nail bed in RA group was lower [(9.82±4.68)% vs (15.56±5.47)%]. In healthy control group, there was rich blood supply of fingertip, moreover, the digital palmar propria artery and nail bed arteries could be displayed clearly and continuously by E-Flow imaging, while the definition and continuity of small vascular flow images in the majority of RA patients were not as good as that in normal controls, and the distribution of blood flow was decreased.

Effective vascular bed and microcirculation perfusion of fingertip reduced and blood flow resistance increased in RA patients. In the end, the vascular system was differently damaged. High frequency ultrasonography combined with E-flow imaging can visually observe vascular distribution characteristics of fingertip and quantitatively evaluate the changes of fingertip′s microcirculation function in RA without clinical manifestations of cardiovascular disease.